In the past, terrorist attacks on buildings have primarily involved the use of conventional weapons such as explosives, incendiary devices and firearms. Thus building defense systems presently in use are designed to protect against such conventional weapons and involve measures such as physical barriers, fire alarms, metal detectors, security checks and armed security personnel. The discovery of nuclear agents and the development of nuclear weapons, airborne chemical and biological contaminates and toxins has provided terrorist groups with sophisticated assault weapons against which render present building defense measures inadequate. Chemical and biological agents may be introduced within a space by various means, purposeful and unintentional. The majority of such spaces are supplied with ventilation and supply and return ducting. The release of vaporized and micro-grained agents contaminate the space and the ventilation system quickly thereafter. If not deterred in some fashion, the contaminant travels with the air to the central air handling equipment where it may be dispersed throughout the system, thereby contaminating the entire area serviced by the central unit.
An assault with a single or a combination of multiple hazardous airborne contaminants may occur with no perception of danger by the potential victim within a building. Such an assault may be particularly devastating when implemented by an aggressor from within the confines of a target building who is willing to sacrifice his or her life in the attack.
Furthermore, HVAC environmental systems are specifically designed to provide conditioned air throughout a facility generally from a central source. This distribution of air throughout a facility may spread a previously isolated contaminant through the building in a matter of minutes which only serves to exacerbate the situation. Thus today's modern sealed structures with central air conditioning and heating and through duct systems need protection from the spread of these contaminants among its occupants. Additionally, protection is needed from colonies of microorganisms which may live and thrive in the duct systems.
Much effort has gone into trying to destroy atmospheric pathogens with only limited success. It has long been recognized that pathogens may be destroyed in the air if they are irradiated with ultraviolet (UV) light at a germicidal wavelength. In order for the UV light to kill microorganisms, the UV rays must directly strike the microorganisms for a sufficient period of time.
The exposure to UV light necessary to kill microorganisms is a product of time and intensity. However due to the dangers to humans of irradiation from widespread use of UV lamps, exposure to UV light has been limited by government regulation. To overcome these problems there have been various attempts to circulate air passed UV sources in enclosures which act to shield the UV irradiation from the room's occupants. Usually, such systems are free standing or wall or ceiling mounted devices which circulate the air in a single room through the enclosure and, accordingly, whose protection is confined to that room.
While such a system may be highly effective to clean the contents of a single room, normal air conditioning and heating ducts would continue to allow circulation of untreated air into and out of a room. This allows untreated air containing pathogens from another room or in the duct system to enter the room and come in contact with the occupants before being sufficiently treated. Consequently, this allows a certain amount of pathogens in a room to enter the duct system prior to being treated by the free standing unit.
Various attempts have been made to place ultraviolet light sources in duct systems to germicidally cleanse fluids such as air as the fluid passes through the duct system. However, the intensity of the irradiation required to treat the air results in significant energy consumption.
These prior art UV systems are not effective against other airborne contaminants such as chemical agents or nuclear agents. Furthermore, even the airborne contaminants that are killed remain in circulation which may lead to false threat detections. One of the most difficult aspects of controlling the effects of airborne contaminants, especially biological materials, is the length of time required to assess and characterize the type and quantity of materials involved. With existing detectors and analyzers, this period is generally measured in minutes, if not hours or days. This period is far too long to wait for a formal assessment before applying appropriate protective measures.
One method to overcome this problem is to assume the facility is under constant attack and to process air using advanced technology continuously. However, this approach unduly wastes valuable resources.
To solve the problems associated with these threats and the deficiencies associated with prior art approaches, it is the object of the present disclosure to present a novel air cleaning method and apparatus that maintains a rapid response to varied threats especially designed for use in high profile buildings subject to hostile attack involving a broad range of nuclear, biological, or chemical air contaminants.
It is another object of the present disclosure to provide an air cleaning system with an air stream contained within a bounded passage. The system comprising: an air stream contamination detection apparatus, an air stream irradiation apparatus, an air stream hydroscopic saturation apparatus and an air stream precipitation apparatus in operational contact with said air stream.
It is still another object of the present disclosure to provide an air cleaning system with a continuous air stream. The system comprising: means for containing the air stream; means for monitoring the air stream for contaminates; means for irradiating the air stream; means for saturating the air stream with a liquid solution; and means for precipitating the liquid solution out of the air stream. The means for monitoring, the means for irradiating, the means for saturating and the means for precipitating are in operational contact with the air stream.
It is yet another object of the present disclosure to provide a method of removing contaminates from a continuous air stream thereby providing a processed air stream. The method including monitoring the air stream for contaminates, irradiating the air stream in an irradiation zone, saturating the air stream with a solution in a saturation zone; and, precipitating the solution contaminates out of the air stream in a participation zone. The air stream of the method flows from the irradiation zone, thru the saturation zone to the precipitation zone.
These and many other objects and advantages of the present invention will be readily apparent to one skilled in the art to which the invention pertains from a perusal of the claims, the appended drawings, and the following detailed description of the preferred embodiments.